Motor vehicle seat

ABSTRACT

The invention relates to a motor vehicle seat that comprises a pivoted backrest that can be swung forward in the direction of a seating of the seat, a longitudinal seat adjuster for adjusting the longitudinal position of the seat, a locking device of the longitudinal seat adjuster for locking a longitudinal seat position previously adjusted, and an unlocking mechanism for unlocking the locking device, and a flexible traction device via which the unlocking mechanism is coupled with the backrest so that the locking device is unlocked when the backrest is swung forward. According to the invention, an actuation element ( 2 ) acts upon the traction device ( 5 ) with a force component at an angle to the direction of extension (E) of the traction device ( 5 ) when the backrest (R) is swung forward, thereby tightening the traction device ( 5 ) and unlocking the locking device.

[0001] The invention relates to a motor vehicle seat according to the preamble of patent claim 1.

[0002] A vehicle seat of this kind comprises a pivotally mounted backrest which can be folded forwards towards the seat surface of the seat; a seat longitudinal adjuster with which the longitudinal position of the seat (position in the vehicle longitudinal direction) can be adjusted; a fixing device for the seat longitudinal adjustment with which a previously set seat longitudinal position can be locked; a release mechanism with which the fixing device can be released in order to be able to set a different seat longitudinal position; as well as a flexible traction means through which the release mechanism is coupled to the backrest so that the fixing device is released when folding the backrest towards the seat surface.

[0003] With a vehicle seat of this kind the fixing device can be released by folding the backrest forwards towards the seat surface so that the seat can be moved forwards to facilitate passengers entering the back of the vehicle. An “easy-entry mechanism” of this kind is widely used in the case of two-door vehicles.

[0004] However there is a problem here in that many users find that the amount of force required to fold the backrest forwards is too high. A considerable force is particularly necessary to release the seat longitudinal adjuster since its locking mechanism for safety reasons is as a rule pretensioned towards the locked state by means of elastic elements.

[0005] The object of the invention is to improve a vehicle seat of the kind already mentioned as regards operating comfort.

[0006] This is achieved according to the invention by providing a vehicle seat with the features of patent claim 1.

[0007] According to this when folding the backrest forward an operating element acts on the traction means with a force component transversely to the extension direction of the traction means so that the traction means are tightened and the fixing device is released. The action of the actuating element on the traction means thereby preferably unfolds so that the actuating element is moved with a component perpendicular to the extension direction of the traction means and is thereby in contact with the traction means, more particularly presses against same (from above).

[0008] As opposed to the known mechanisms for releasing the seat longitudinal adjuster by folding the backrest forwards, here in order to tighten the traction means through which the release is to be actuated, the force is not exerted in the extension direction of the traction means on one end of the traction means, but rather a force is exerted with a component across the extension direction of the traction means on a section of the traction means. The resulting force need thereby not be aligned exactly perpendicular to the extension direction of the traction means, as corresponds to one embodiment, but it is sufficient if the force exerted by the actuating element on the traction means has at least a force component transverse to the extension direction of the traction means.

[0009] With the solution according to the invention however compared to the arrangements known from the prior art a reduction of the force to be applied by folding the backrest forwards is reached by utilising the effects as used with a block and tackle.

[0010] Furthermore the arrangement according to the invention has the advantage that the traction means can be completely pre-fitted on the seat lower frame since no connection is required between the traction means and backrest. For the backrest can indeed act through the actuating element on the traction means fixed on the lower frame.

[0011] The actuating element preferably acts on a section of the traction means which is spaced from the backrest-end of the traction means.

[0012] The actuating element is advantageously formed rotationally symmetrical relative to an axis and is mounted rotatable about this axis which can be achieved in particular through the use of a roller as actuating element. However as actuating element can also be used, in the case of a vehicle seat, elements which are provided for other purposes, such as e.g. an axle shaft of a seat axle. Furthermore the actuating element can be formed also through a slider which preferably consists of plastics.

[0013] Several actuating elements can be provided for acting on the traction means for the best possible reduction of the force to be applied whereby they act on the traction means similar to a block and tackle with several loose rollers.

[0014] The traction means itself is fixed by its backrest end at a suitable fixing point on the seat frame, e.g. on a seat side part. The fixing point is selected so that when the backrest is folded forwards the fixing point is not moved, more particularly is not pivoted together with the backrest.

[0015] Furthermore in a further development of the invention a guide element is provided with which the traction means are guided so that a section of the traction means runs at a suitable angle, more particularly perpendicular to the active direction of the actuating element. This guide element is preferably formed by a roller (“fixed roller”) which interacts with the actuating element provided for acting on the traction means for obtaining the block and tackle effect.

[0016] The actuating element can be readily arranged so that when the backrest is folded forwards by pivoting it can be brought into engagement with the traction means. For this the actuating element is mounted on a body which is movable, more particularly pivotal when the backrest is folded forwards.

[0017] Furthermore it can be proposed that the backrest when folding forwards acts with a follower on a stop associated with the actuating element in order to bring the actuating element into engagement with the traction means. The follower and stop are thereby positioned so that the release process only starts after folding the backrest forwards about a certain minimum amount.

[0018] Further features and advantages of the invention will be apparent from the following description of an embodiment with reference to the drawings.

[0019] They show:

[0020]FIG. 1 an arrangement with which a backrest when folded forwards to release the fixing device of a seat longitudinal adjuster acts on a traction means, in the case of a backrest raised up substantially vertical;

[0021]FIG. 2 the arrangement of FIG. 1 with the backrest folded forwards towards the seat surface;

[0022]FIG. 3 a diagrammatic view of a motor vehicle seat.

[0023]FIG. 3 shows diagrammatically a frame G of a motor vehicle seat with a seat side part T which is connected through a lever pair H1, H2 vertically adjustable to the top rail O of a rail longitudinal guide consisting of two rails O, U displaceable relative to each other in the longitudinal direction L and which serves for holding a seat trough with seat cushion. The rail longitudinal guide is lockable by means of a fixing device V so that the seat longitudinal position actually set is fixed. The fixing device V is for safety reasons normally pretensioned by means of elastic elements towards its locked state so that the seat longitudinal position is constantly fixed unless the locking of the fixing device B is actively released against the action of the elastic element.

[0024] A backrest frame R of a seat back is attached for pivotal movement to the seat side part T and in turn can pivot in a useful region in order to set the backrest incline corresponding to the requirements of the relevant seat user and which on the other hand can be folded forwards towards the seat surface (or seat cushion) in order to release the fixing device V and to slide the seat with the backrest folded forwards (easy-entry function). For this the backrest frame R is coupled to the fixing device V, which will be described with reference to FIGS. 1 and 2, through a coupling mechanism K (diagrammatically shown in FIG. 3).

[0025] An easy-entry mechanism of the type described with reference to FIG. 3 is known from for example WO 00/55002 (apart from the novel action according to the invention of the backrest frame R on the coupling mechanism K which will be described with reference to FIGS. 1 and 2), so that the details regarding the design of this mechanism will not be described. Instead in this respect reference is made to the WO 00/55002A1.

[0026]FIG. 1 shows a part of the backrest R of the vehicle seat according to FIG. 3 which is attached for pivotal movement on a projection FT of a seat side part T of the vehicle seat. The backrest R can be set in different useful positions by pivoting about its swivel axis on one side to support the back of the occupant. On the other hand the backrest can be folded forwards towards the seat surface in order to release the easy-entry mechanism explained with reference to FIG. 3.

[0027] In FIG. 1 the backrest R is located in a useful position in which it is set substantially perpendicular.

[0028] On the projection FT of the seat side part T on which the backrest R is mounted for swivel movement a body 1 formed as a cam is mounted to pivot at the same time about an axis 10. The pivotal body 1 has a stop 15 associated with a follower 16 which when the backrest R is folded forwards towards the seat surface is pivoted clockwise together with the backrest and thereby finally moves into engagement with the stop 15 so that the pivotal body 1 on folding the backrest R further forward is entrained by the follower 16 through the stop 15, i.e. is pivoted about its axis 10.

[0029] A roller 2 is mounted rotatable about an axis 20 on a lug 11 of the pivotal body 1. Underneath the roller 2 a section 50 of a traction means 5 (e.g. in the form of a cable) is guided which serves to couple the backrest R to the fixing device of a seat longitudinal adjuster. By tightening the traction means 5 the fixing device can be released for which the traction means 5 is connected by one end to the fixing device. The other end 51 of the traction means 5 (backrest side end ) is formed as a nipple and is suspended through a stop 52 from the seat side part T. The traction means 5 extends by its section 50 beneath the pivotal body 1 to a roller 3 (fixed roller) mounted rotatable on the seat side part about an axis 30 and which serves as guide element and by means of which the traction means is guided towards the fixing device which is to be actuated. The traction means is guided in a Bowden sleeve 6 along the connecting path from the roller 3 to the fixing device which is to be actuated. The Bowden sleeve is supported on a support element 60 which is provided on the seat side part T.

[0030] If the backrest R is folded forwards from its substantially perpendicular position shown in FIG. 1 towards the sitting surface of the seat then the arrangement illustrated in FIG. 1 occupies the state shown in FIG. 2.

[0031] On folding the backrest R forwards the follower 16 which is connected in suitable manner to the backrest R and at first is spaced from the stop 15 of the pivotal body 1 is moved (clockwise) and thereby strikes the stop 15 after a certain pivotal angle. Only at this moment does a (swivel) movement of the body 1 start which is entrained by the follower 16 and the associated stop 15 and is thus pivoted together with the backrest R. The pivotal body 1 can be pretensioned by means of an elastic element (not shown) in the direction of its position illustrated in FIG. 1 (in which it does not act on the traction means 5) so that it is entrained by the follower 16 against this pretensioning force if the backrest is folded forwards and thereby acts on a section 50 of the traction means 5.

[0032] When swivelling the body 1 clockwise (corresponding to folding the backrest R forwards) its nose 11 is moved with the roller 2 mounted rotatable thereon towards the section 50 of the flexible traction means extending underneath the body 1. The roller 2 thereby acts with a force component which runs perpendicular to the extension direction of the said section 50 of the traction means 5 onto same. The traction means 5 is thereby each time guided in suitable guide channels of the rollers 2, 3. In addition further guide means can also be provided on the seat side part in order to guide the section 50 of the traction means 5 running underneath the rotary mounted roller 2 along a defined path so that that roller can act thereon.

[0033] The said section 50 of the traction means 5 is hereby curved and the traction means tightened overall. A force thus acts on the part of the traction means 5 guided in the Bowden sleeve 6 along a traction direction Z towards the cable roller 3 serving to deflect the traction means 5 (and thus away from the fixing device of the seat longitudinal adjuster). The fixing device of the seat longitudinal adjuster is hereby as known from the prior art released by the locking elements of the fixing device being lifted from their locking position against the action of elastic elements.

[0034] It is presently of importance that to tighten the traction means 5—as opposed to the arrangements known from the prior art—no force is exerted on the backrest side end 51 of the traction means 5 in the extension direction of the corresponding section 50 of the traction means 5. The backrest side end 51 of the traction means 5 is rather fixed spatially and is not moved when folding the backrest forwards. Instead of this an action of an actuating element on a section 50 of the traction means takes place perpendicular to its extension direction through which this section is curved. This has the result of tightening the traction means 5 (corresponding to a shortening of the effective length of the traction means) through which the fixing device of the seat longitudinal adjuster can be released. In order to slide the traction means 5 with its section guided in the Bowden sleeve 6 about a certain amount in the traction direction Z which is sufficient to release the fixing device there is a need for a larger adjusting path of the roller 2 acting on the traction means 5 compared with an actuating element which acts with a tractive force directly on the backrest side end 51 of the traction means 5. Since the work to be applied to overcome the pretensioning force of the elastic elements of the fixing device is the same in both cases this means that with the present solution lesser force is to be applied. 

1. Motor vehicle seat with a swivel mounted backrest which can be folded forwards towards a seat surface of the seat a seat longitudinal adjuster by which the longitudinal position of the seat can be set; a fixing device for the seat longitudinal adjuster by which a previously set seat longitudinal position can be locked; a release mechanism by which the fixing device can be released; and a flexible traction means through which the release mechanism is coupled to the backrest so that the fixing device is released when the backrest is folded forwards, characterised in that the traction means (5) are fixed in the end area (51) on the backrest side to a fixing point (52) which is not moved when the backrest (R) is folded forwards, and that when folding the backrest (R) forwards an actuating element (2) acts on the traction means (5) with a force component transversely to the extension direction (E) of the traction means (5) so that the fixing device (F) is released.
 2. Motor vehicle seat according to claim 1, characterised in that the actuating element (2) acts on a section (50) of the traction means (5) which is spaced from the backrest side end (51) of the traction means (5).
 3. Motor vehicle seat according to claim 1 or 2, characterised in that the actuating element (2) is rotationally symmetrical.
 4. Motor vehicle seat according to claim 1, characterised in that the actuating element (2) is mounted rotatable.
 5. Motor vehicle seat according to claim 3, characterised in that the actuating element (2) is formed by a roller.
 6. Motor vehicle seat according to claim 3, characterised in that the actuating element (2) is formed by a section of an axis.
 7. Motor vehicle seat according to one of claim 1, characterised in that the actuating element (2) is formed by seat components which have another function other than tightening the traction means.
 8. Motor vehicle seat according to claim 1, characterised in that the actuating element (2) is formed by a slider, which is preferably made of plastics.
 9. Motor vehicle seat according to one of claim 1, characterised in that when folding the backrest (R) forwards at least two actuating elements act on the traction means.
 10. Motor vehicle seat according to claim 1, characterised in that the traction means (5) are fixed in the region of the end (51) nearest the backrest on a fixing point (52) on the seat frame.
 11. Motor vehicle seat according to claim 10, characterised in that the fixing point (52) is not pivoted when the backrest (R) is folded forwards.
 12. Motor vehicle seat according to claim 1, characterised in that a guide element (3) is provided with which the traction means (5) are deflected so that a section (50) of the traction means (5) run at an angle, preferably perpendicular to the active direction of the actuating element (2).
 13. Motor vehicle seat according to claim 1, characterised in that the actuating element (2) when folding the backrest (R) forwards is moved, more particularly swivelled so that it engages with the traction means (5).
 14. Motor vehicle seat according to claim 13, characterised in that the actuating element (2) is mounted on a body (1) which can swivel when folding the backrest (R) forwards.
 15. Motor vehicle seat according to claim 1, characterised in that the backrest (R) when folding forwards acts by a follower (16) on a stop (15) which is associated with the actuating element (2) in order to bring this into engagement with the traction means (5).
 16. Motor vehicle seat according to claim 15, characterised in that the backrest (R) when folding forwards from a useful position only then acts by the follower (16) on the stop (15) after the backrest (R) has been folded forwards about a defined angle.
 17. Motor vehicle seat according to one of claims 14, 15 or 16, characterised in that the stop (15) is provided on the pivotal body (1).
 18. Motor vehicle seat according to claim 1, characterised in that guide means are provided to guide the traction means (5) in the region of the actuating element (2). 